1. Field
Embodiments described herein generally relate to systems and methods for adjusting a concentration of moisture of a veneer. More particularly, such embodiments relate to systems and methods for producing a veneer having a moisture concentration above a minimum moisture concentration level.
2. Description of the Related Art
Veneer products, e.g., plywood, laminate veneer lumber (LVL), laminated veneer boards (LVB), and the like, are produced by bonding a plurality of veneers (or one or more veneers and a core substrate) together with an adhesive and curing the adhesive to form the veneer product. The moisture concentration of the veneer upon skiving, cutting, slicing, sawing, or otherwise removing from a wood source or body such as a log typically ranges from about 60 wt % to about 170 wt %, based on a dry weight of the veneer. Prior to adhering the veneers to one another and/or to a core substrate, the veneers are dried in order to reduce the moisture concentration to a desired level, e.g., less than about 40 wt % moisture, before applying the adhesive and bonding the veneers to one another. Various techniques for drying the veneers have been developed, e.g., heating in an oven, contacting with a stream of hot air, air drying, and other methods, in order to reduce the moisture content to the desired level. The adhesive is applied to one or more surfaces of the dried veneers, the veneers are properly oriented with respect to one another, placed into contact with one another, and the adhesive is at least partially cured, usually under pressure and heat, to produce the veneer product.
Drying the veneer, however, typically does not produce veneers having uniform moisture concentration. Instead, the moisture concentration about a particular veneer, as well as the moisture concentration between different veneers, will usually vary. In fact, the moisture content about the surface of any given veneer can range anywhere from none, i.e., completely dry, up to about 40% moisture or more, based on the dry weight of the veneer, depending on the particular location about the veneer. As such, different locations or regions about a particular veneer can range from having no moisture to up to about 40%, based on the dry weight of the veneer, after drying. Adhering veneers that do not have a desired moisture concentration, e.g., fall below a minimum moisture concentration, results in poor bonding between the veneer(s) or the veneer and a core substrate.
In order to counteract the poor bonding between a veneer having a moisture concentration below a certain minimum level and another veneer or a core substrate, an increased amount of adhesive is typically applied to the substrate and/or the veneer. The increased amount of adhesive helps to reduce the negative effects caused by low moisture concentration in the veneer. In addition to the increased costs associated with the increased amount of adhesive used to produce the veneer product other negative effects can also be experienced. There is a need, therefore, for improved systems and methods for producing a veneer having a moisture concentration above a minimum moisture concentration level.